Talk:HL7 proposed guidance on use of displayName(V3 CD) and Text (V2.x CNE,CWE)

Outstanding issue(s):

1. Interface terms that are not supported by code systems currently do not have a place in the CD data type. The following options need to be considered:
   1. Original text may be used if the CD.code value is not already derived from prior supplied original text value (dangerous).
   2. Translation may be used if the interface term is supported by another code system.
   3. There is no capability in the current CD, CNE or CWE data types to specify the desired interface term (term to display to the user). Proposals to address this should be submitted.
      1. e.g. Add new data type component "Preferred Display Text". This field represents the sender's desired representation of the concept to the receiver. The preferred text may be an approved description from the code system or alternative text that does not alter the meaning of the concetp as defined by the code system.
2. Need to add guidance for use of original text (who is the originator?)
3. How do extension terminologies work in this environment? Give examples for each code system.
   1. LOINC - LOINC currently only supports three types of display text; fully specified name, short common name and long common name. As long as a LOINC extension conforms to the current rules for extending the terminology, any of these three representations would be valid to include as the description in any of the data types.
   2. SNOMED CT - Given that there is no currently approved way to specify a description ID in a message, there is no difference in the use of an extension description or a core concept description.
4. Post-coordination in v2.x? Use of displayname for postcoordinated expressions? (pending outcome of post-coordination task for OO)

Use Cases

Public Health Use Case

Reference testing for Salmonella

Public health labs need to be able to send 2 different display names for the same concept in the same message.

1. First we will report identification to the subspecies level– even here the lab SME might have a preference for description, that is NOT the same as the preferred term in SNOMED, or might not even be in SNOMED yet:

e.g. Salmonella enterica subspecies I (JTC - There is no subspecies I, this is a serogroup. It is listed in SNOMED CT as a child of serogroup O:3,10.) The SNOMED CT concept ID is [398342009] Salmonella I, group O:3,10

1. Then the lab reports the serovar name of the Salmonella in question using LOINC 20951-0

Serovar Fufu (SNOMED CT conceptID 41677008)

1. The lab also wants to report the antigenic formula using LOINC 56475-7

(SNOMED CT description Salmonella 3,10:z:1,5) I 3,10:z:1,5 (

Both serovar name and antigenic formula belong to the same SNOMED concept: 41677008^Salmonella Fufu (organism)

If descriptionIDs cannot be messaged, would it be legal to create a local code system to unambiguously message those descriptions? If not, one option would be to have explicit result value sets for each LOINC code, other options?